switching it up
by rinry-rockmine
Summary: If you had told him, years ago, that he would end up kneeling on their bed with his ass up, face down, waiting to be lubed up, Len Kagamine probably would have told you to go fuck yourself.


**hello, it is i, back with more sin that no one asked for :^)**

 **this is literally pure sin kiddies stay away. this is really self indulgent and i am so s orry**

 **disclaimer: someone take len kagamine away from me he deserves better**

If you had told him, years ago, that he would end up kneeling on their bed with his ass up, face down, waiting to be lubed up, Len Kagamine probably would have told you to go fuck yourself.

The subject is first brought up at breakfast one cloudy morning. He's munching mundanely on some bland cer

eal, staring out the window, when suddenly Rin pulls out the chair across from him and plops into it, crossing her long legs in front of her and staring at him with those incredibly blue eyes. She has The Look, the look that tells Len that whatever comes out of her mouth next will cause him loads of trouble, and, most often, some pain.

"So," she begins, tugging on her favorite pair of combat boots and beginning to lace them up. "I've been thinking."

Mouth half full with cereal, Len replies, "That's never a good conversation starter."

She rolls her eyes and kicks him in the shin, not hard enough to cause too much pain, but enough to sting a little. She huffs in irritation. "Anyway, after last night, I was thinking that maybe we could try switching things up. You know, in the bedroom."

He watches her fingers weave the laces through the last few holes, tying them up in a nice little bow. He wasn't against the idea. He wasn't unsatisfied with their sex life, but he could agree that trying something new could be beneficial. "What do you have in mind?"

Filling his mouth with another bite of cereal, he sees her staring at the ceiling, refusing to meet his eyes. Another red flag. Rin isn't exactly bashful about much (unlike him, who got so embarrassed the first time they tried having sex they had to stop and settle for cuddling instead), so if she's embarrassed about whatever she's thinking, it's gotta be pretty extreme. Swinging her feet back and forth under her seat, she finally makes eye contact. The wildness in her eyes makes him both nervous and excited. "I want to fuck you. In the ass."

That's how his cereal ends up spewed out across the kitchen table, milk dripping down his chin as he stares at his animated girlfriend in bewilderment. It takes him a few moments to gather his thoughts enough to even speak. When he does, it comes out in chopped sentences.

"You want. To fuck. Me. In the ass. My ass. You want to fuck my ass."

"Bingo," she sing songs, her initial shyness or whatever that was gone.

"Why," he hisses, finally senseful enough to grab a napkin and wipe the milk from his chin and the corner of the table.

His cheeks are growing hotter the more he thinks about it. The thought of leaving himself utterly and completely at her mercy… He shivers.

"Come on. When have I ever shut up about your ass? Anyway, I'm tired of always being the one of the receiving end. I want to see what it would be like… The other way around," she explains, enthusiastic and talking with her hands again, sending a rush of affection through him.

Now he's the one that can't look her in the eye. He stares at the standing pool of milk and cereal on the table. He runs a hand through his bangs, sighing deeply. He's such a pushover.

"What are you planning on using?"

He sees her grin ear to ear out of the corner of his eye, obviously understanding that his answer isn't a flat out no. She starts talking about how she'd thought that they'd go out and look for something together, so whatever they picked would be something he'd be comfortable with. Just the thought of going into one of those stores with his girlfriend and looking for a dildo that was going to penetrate him was almost enough for him to die of embarrassment. But then again, he does want to make sure she doesn't go alone, because, knowing her and her lack of self control, she would definitely get something way too unreasonable. He imagines the shapes and sizes and accessories and all the possibilities and almost passes out on the spot.

He is so whipped.

So that's how ends up in that oh-so-pleasant position, waiting for the inevitable. They had chosen a night where no one else was in the house and guaranteed to not be back until sometime the next day. They'd went out to dinner together and it was really nice, but the entire time Len couldn't help but dwell on what was to come. They'd each taken steps to prepare themselves for the night ahead of time. Rin done plenty of research online and in magazines for advice on how to make it as pleasurable as possible. Len had taken the time between the first discussion and the anticipated night to begin learning how to prepare himself down there. It had been extremely uncomfortable at first, so much that he scared to the point that he would quit before he was done, but after a couple times of practice he had gotten more comfortable with the idea of something going there. Still, nothing could help him escape the nerves he felt as he waited for what seemed like forever for Rin to search through her bag for lube.

His anxiety builds when he hears her pleased hum when she finds the lube. He sits back and watches as she unscrews the cap. She generously applies some to her fingers, licking her lips in a mixture of excitement and what might be nervousness. She glances up, suddenly seeing the worried eyes of her lover, and stops for a moment. All the sudden her hand is on his cheek, warm and familiar, already causing a rush of relief to roll through him. Her thumb brushes against his cheek bone. "Hey," she says seriously, staring him deep in the eyes. "You know you don't have to do this for me, right?"

Of course he knows. Despite all her toughness and stubbornness, he knows that she would never, ever do anything to hurt him or that he wouldn't like. "I know. Don't get me wrong. I want this too, I'm just. Nervous. Really nervous."

She gives a light laugh, that soft tinkle she has sometimes that always sends him reeling. "Don't be. Just relax and let me take care of you."

The preparation process is awkward, of course. They've never done anything like that together before, so no amount of self preparation would completely ready either of them without some ounce of discomfort. When they're sure he's ready, Rin finally brings out the dildo. Just the sight of it stirs up the embarrassing memories of walking into that toy store and telling the clerk their purpose. They'd settled on something manageable, a size that wasn't huge but definitely wasn't small either.

He returns to his former position, on his knees with his ass exposed. His cheeks are red enough for it to be like their first time again. In a way, it kind of is. The thought arouses him and does nothing to help the flush.

After donning the harness and making sure everything was in order, he hears Rin slathering lube onto the toy. When finished he feels a petite hand lay just above his ass crack. "You ready?"

Training his eyes onto the white sheets in front of him, Len takes a deep breath. "As I'll ever be. Go ahead."

The first thing he feels in her warm finger, guiding the head toward his entrance slowly. He then feels the cold and slick toy begin to probe inside. The feeling is so foreign and strange that he almost tenses, but he restrains himself because he knows that will only make it harder. He forces himself to relax and take deep breaths as she gradually slides the toy in bit by bit. The process is agonizingly slow until all the sudden something just slides forward and a gasp escapes his mouth.

"Good or bad gasp?"

Exhaling deeply, he replies breathily, "Weird gasp. I mean- I'm pretty sure it was a Good Gasp."

"So you want to keep going?"

He only nods, very aware that there is now a penis shaped object up his anus. He stares at the sheets wordlessly, likely on the brink of an existential crisis. However, his ability to focus weakens when it suddenly begins moving again. After pressing a little deeper, Rin begins to thrust into him. Without a thought, he was suddenly moving his hips on instinct to meet her thrusts. She quickens her pace, eliciting soft and quiet gasps from the boy. She presses deeper with each thrust, exploring territory completely unknown. It's experimental, and when she's comfortable with the movement of thrusting, she slows up and focuses solely on getting deeper and finding that special spot.

She alternates fast and slow thrusts while making an effort to find his prostate. He continues to roll his hips to meet her thrusts, never getting just enough friction. Her hands are suddenly on his hips, gripping them tightly like he always does to her. He wonders if this is how she feels each time he penetrates her, vulnerable and putting her trust completely in him. He doubts he's ever felt more physically exposed in his life. The feeling is thrilling, especially when she thrusts into him quickly and impatiently. His shallow breaths are turned to shocked gasps when she finally finds the golden spot. He lets out a loud and embarrassing moan when she hits it just right, letting her know she just hit the jackpot. He can practically feel that smug smirk she wears as she starts to target that spot deliberately.

The room feels like it's getting hotter by the second. Rin keeps up her alternating paces, somehow pressing deeper with each thrust. Len soon finds he needs to grab onto something, anything, and clenches onto the sheets below so tightly his knuckles turn white. Moans are coming louder and more frequent involuntarily, so he bites down onto the sheet as to muffle himself in order to keep at least some amount of dignity. Rin seems to notice his attention and laughs, a low chuckle that sends shivers up his spine. "Don't be shy, Len. I love it when you get loud."

All this is getting to be too much. He feels like he's trapped in his own skin, too hot and too aroused. He's so hard it hurts, but he's afraid to try pleasuring himself; he doesn't think one shaky arm will be enough to hold himself up at this point. He knows he's on the brink, and braces himself for climax, but suddenly, the thrusting stops and the toy is leaving him with a lewd sounding "pop."

He feels the absence immediately and lets out a whine he'd never in his wildest dreams imagined hearing out of himself. Breathless, he manages to choke out, "Wha- Why... Did... You... Stop? Keep... _Ah_ , going."

Rin gives him nothing but a curt, "Flip over."

He obeys, still breathing heavily. He wants it back in him so bad it's shameful. At this point, he'll do anything she says just to feel that way again.

She parts his legs and leans over him, peeling off her shirt waiting as he fumbles to unhook the clasps of her lacy black bra. He finally can actually see her now, bare chested and wearing that god damned harness. The straps around her thighs and hips look incredible. The sight is so bizarre and wonderful it makes Len feel dizzy. She grins down at him wickedly. "I finally get why you always want to see my face when we fuck. The other way around feels so impersonal."

She leans even deeper and meets his mouth with hers. Their lips move together sloppily. It's all too hot, but he obliges when her tongue slips against his bottom lip, pressing further. Her fingers tangle in his messy ponytail and effectively mess it up. At the same time, that member inches near his entrance again, pressing in as it did before. He gasps unwillingly again, only to have it swallowed up by Rin. As she begins those quick thrusts again her mouth leaves his in favor of his jawline and exposed neck. She gives each spot special attention, making sure without a doubt her kisses will leave bruises. It's that kind of possessiveness about her that drives him crazy, in the most amazing way. His hands travel from her waist and up her back, lightly scraping his short fingernails across it. She gives a satisfying shiver.

The moaning starts again before he can stop it. After a particularly feminine and loud one, the thrusting stops and she leans back and looks down at him with wicked and hungry blue eyes. He realizes her reason and floods with red, covering his face in embarrassment. "Can't help it, okay? It just feels... Really..."

Her hands pull his from his face and hold his wrists down on either side of his face. Her eyes are taking in every inch of him and it makes him flush even harder, but he doesn't fight. He's about to snap and ask why she's looking at him so intently, but she beats him to it.

"You're beautiful. You're so fucking beautiful."

His eyes widen and his mouth hangs open. His biting words die in his throat, unable to produce any sound other than a confused hum.

"You're beautiful. I've always known that, but I've never fully taken how pretty you are until now. You're gorgeous."

He just might implode from embarrassment. His girlfriend is calling him beautiful. He's about to protest that you don't call boys beautiful, you call them handsome, when she suddenly thrusts right into his prostate, making him gasp loudly.

"Your eyes are such a dark blue right now. Your eyelashes are so long and I like the way they flutter every time you gasp," she begins shamelessly, leaning down to kiss each of his eyelids while beginning to pick up a pace again.

Her hands grip his wrists tightly and let go, tracing the visible veins and making him quiver under her. "Your wrists are slender and pale. They make you look really graceful and sophisticated when you talk with your hands."

Her fingers are in his hair again, running through his bangs and long strands. "Your hair is getting pretty long and you probably take more care of it than I do. I like it when it's loose and hardly in a ponytail like this."

Her thrusts are slowly and deliberately hitting his prostate now. He tries to close his mouth and stifle the many noises, but suddenly her thumb is tracing his bottom lip and causing him to reflexively exhale in pleasure.

"Your lips are always pink and I like how red and swollen they look after we kiss. I like knowing that I did that. I'm the only one that gets to do that."

He can't help it now. She pushes in possibly the most spot on thrust yet and makes him moan, perverse and noisy. Her lips form a shit eating grin and he can't help but glare at her with red refusing to leave his cheeks.

"Your voice. That's my favorite. I fucking love it when you sing, when you laugh, when you speak, when you whisper, and especially, when you fucking _moan_ and _gasp_ like this. You're so fucking beautiful, especially when you're all messed up like this, Len- _chan_."

That one syllable spoken in a low voice like that goes straight to his dick. She saves that honorific only for when she's talking down to him like this. It's humiliating and degrading and so fucking hot.

"You hear that, Len-chan? I like it when you're messed up. I like it when your hairs everywhere and when your lips are red and swollen and when there are bruises on your throat and when you look at me with those hazy eyes and red cheeks and I love it when I make you _scream_."

Just to prove it she thrusts even harder and faster. Her fingernails dig into his shoulders as she suddenly latches onto one of his nipples and begins to suck, dragging her tongue around it in agonizing swirls. He's practically whining at this point, fisting the sheets again and throwing his head back to stare at the ceiling, vision blurry and shaking. There's a hand on his dick, finally there to relieve some of that aching hardness. He practically cries in relief, his moans beginning to sound something like a garbled "Rin-chan, Rin-chan, please, please Rin-chan."

He knows he's getting close again. Rin has moved her mouth to give attention to his other nipple and toys with the other one with her finger. She pumps him fast and hard while continuing to thrust mercilessly into that sweet spot. He tries to warn Rin that he's close, but he can't seem to form full words anymore. But she seems to understand, and only increases the speed her activities in earnest. She leans forward and breaths hotly against his ear. "Are you ready to come, Len-chan? Do you want to come?"

He knows better than to resist, so he nods eagerly and breaths out a succession of urgent yes's. "You have to say it, Len-chan. Tell me what you want."

Exasperated, he pushes any amount of shame out of his mind and almost yells, "Yes, I want to come, ah, please, Rin-chan."

She giggles evilly and nibbles on his earlobe. Finally, she whispers, "Then do it."

And he does. Cum splatters out of him and all over his stomach and hers. She continues to pump his cock as the liquid comes out in long spurts, allowing him to ride out the orgasm for all its worth. She finally pulls out when he's all done. While he catches his breath and is actually able to see straight again, she unstraps the harness and lets the thing drop to the floor, crawling out of it and next to him, wrapping herself around him happily.

Like usual, she insists on being the Big Spoon, though this time it does seem pretty fitting. She strokes his shoulders and arms and places gentle and chaste kisses on the back of his neck. He stares forward, his heartbeat finally slowing down. He's kind of in a state of disbelief. Did any of that really just happen? Did he really just get hit from behind by his girlfriend.

The soreness all over his body says yes. She snuggles into his back behind him and asks, "How are you doing?"

He only grunts.

"Did you like it?"

Did he? It's almost laughable. _Like_ wasn't a strong enough word. He had loved it. He wanted to do it again. He wanted them to do this very, very often. Maybe even more than the other way around. He wanted to change sizes and shapes and different toys and-

"It wasn't _bad_."

It wasn't.

 **i literally wrote this at 2 AM in my sisters basement using my brother in laws iphone hotspot this was how much i felt the need to write this**

 **idk i have this thing for rin finding len really beautiful because he is? i think im projecting?**

 **anyway i know people have asked me to write other ships and situations and i am happy to! it just takes a while! please keep requesting it gives me strength. just pm me or drop it in the reviews and ill try to do it asap bc i need the practice lol**

 **thank you for reading!**


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